question about AR-15 buffers

[scientific]

I've acquired a stripped lower and am shopping for the rest of the parts I'll need. I'm looking at getting a CMMG midlength upper with 16" barrel. What buffer is best matched to the midlength gas system with this barrel length?

 

[taliv]

assuming a carbine stock, a standard carbine buffer is fine.

 

[Gordon]

I think it depends on stock also (and caliber)

 

[scientific]

Probably using a magpul ctr stock.

under what conditions might I want to use an H buffer?

 

[Gordon]

You want an H1 buffer then with a CTR and Midlength, thats what my research has led me to at least.

 

[sarduy]

carbine stock/buffer is good to go.

 

[SHvar]

I bought an H buffer to try out in my 16 inch AR, and it slows the actions a bit, reduces the recoil a bit. Im sure it increases dwell time in the chamber allowing the spent case to extract a bit better.
Trying different weight buffers and seeing the effects would be something for each rifle to get a bit different results.

 

[Bartholomew Roberts]

I run a standard carbine buffer in my midlength. If you have increased pressure (carbine gas/16" barrel or midlength gas/16" barrel + suppressor), I think the H-buffer is the way to go.

I've played with buffers as heavy as the MGI Rate-Reducing Buffer (7oz) and I've come to the conclusion that the advantage of changing the subjective feel of the recoil isn't worth the reliability issues playing around with the buffer causes.

 

[scientific]

I'm still a little confused about the relationship between barrel length, gas system length, and buffer weight.

does a longer barrel increase pressure?
does a shorter gas system increase pressure?

which barrel length and gas system length is the standard carbine buffer ideal for? and which barrel length and gas system length is the H buffer ideal for?

 

[Zach S]

I use the H1 for midlengths, H2 for carbines.

Some folks go heavier (like a 9mm buffer in a CAR), but it may short-stroke with some of the weaker ammo such as wolf.

I dont use wolf ammo, but I might have to in a pinch, so I dont go very heavy.

 

[Bartholomew Roberts]

The standard carbine buffer and spring were designed for the XM177, a 10.5"/11.5" barrel with moderator and with carbine gas. The H-buffer was developed for the M4 carbine, a 14.5" barrel with A2 flash hider and carbine gas.

Check out some of the threads in the Rifle Forum Reading library for a better discussion of gas pressures and the AR operating system.

 

[briansmithwins]

CMMG midlength upper with fixed A1 stock for me. The standard rifle buffer works perfectly fine. 55gr Wolf, XM193, 50gr JHPs, 75gr JHPs: they all function fine. BSW

 

[Rubber_Duck]

I use an H2 buffer in a Bravo Company carbine upper with 16" barrel, not much difference between H and H2 so I opted for the H2 to slow the unlocking process a bit. My AR cycles Wolf and Brown Bear ammo just fine.